Electrical properties of photoconductor using Ga2O 3/CuGaSe2 heterojunction

Kenji Kikuchi; Shigeyuki Imura; Kazunori Miyakawa; Misao Kubota; Eiji Ohta

doi:10.1557/opl.2013.1013

Electrical properties of photoconductor using Ga₂O ₃/CuGaSe₂ heterojunction

Kenji Kikuchi, Shigeyuki Imura, Kazunori Miyakawa, Misao Kubota, Eiji Ohta

Department of Applied Physics and Physico-Informatics

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Abstract

The feasibility of using a photoconductor with a Ga₂O ₃/CuGaSe₂ heterojunction for visible light sensors was investigated. CIGS chalcopyrite semiconductors have both a high absorption coefficient and high quantum efficiency. However, their dark current is too high for image sensors. In this study, we applied gallium oxide (Ga ₂O₃) as a hole-blocking layer for CIGS thin film to reduce the dark current. Experimental results showed that the dark current was drastically reduced, and an avalanche multiplication phenomenon was observed at an applied voltage of over 6 V. However, this structure had sensitivity only in the ultraviolet light region because its depletion region was almost completely spread in the Ga₂O₃ layer since the carrier density of the Ga₂O₃ layer was much lower than that of the CIGS layer. These results indicate that the Ga₂O₃/CuGaSe₂ heterojunction has potential for use in visible light sensors but that we also need to increase the carrier density of the Ga₂O₃ layer to shift the depletion region to the CIGS film.

Original language	English
Title of host publication	Compound Semiconductors
Subtitle of host publication	Thin-Film Photovoltaics, LEDs, and Smart Energy Controls
Pages	391-395
Number of pages	5
DOIs	https://doi.org/10.1557/opl.2013.1013
Publication status	Published - 2013
Event	2013 MRS Spring Meeting - San Francisco, CA, United States Duration: 2013 Apr 1 → 2013 Apr 5

Publication series

Name	Materials Research Society Symposium Proceedings
Volume	1538
ISSN (Print)	0272-9172

Other

Other	2013 MRS Spring Meeting
Country/Territory	United States
City	San Francisco, CA
Period	13/4/1 → 13/4/5

ASJC Scopus subject areas

Materials Science(all)
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

Access to Document

10.1557/opl.2013.1013

Cite this

Electrical properties of photoconductor using Ga₂O ₃/CuGaSe₂ heterojunction. / Kikuchi, Kenji; Imura, Shigeyuki; Miyakawa, Kazunori et al.

Compound Semiconductors: Thin-Film Photovoltaics, LEDs, and Smart Energy Controls. 2013. p. 391-395 (Materials Research Society Symposium Proceedings; Vol. 1538).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Kikuchi, K, Imura, S, Miyakawa, K, Kubota, M & Ohta, E 2013, Electrical properties of photoconductor using Ga₂O ₃/CuGaSe₂ heterojunction. in Compound Semiconductors: Thin-Film Photovoltaics, LEDs, and Smart Energy Controls. Materials Research Society Symposium Proceedings, vol. 1538, pp. 391-395, 2013 MRS Spring Meeting, San Francisco, CA, United States, 13/4/1. https://doi.org/10.1557/opl.2013.1013

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abstract = "The feasibility of using a photoconductor with a Ga2O 3/CuGaSe2 heterojunction for visible light sensors was investigated. CIGS chalcopyrite semiconductors have both a high absorption coefficient and high quantum efficiency. However, their dark current is too high for image sensors. In this study, we applied gallium oxide (Ga 2O3) as a hole-blocking layer for CIGS thin film to reduce the dark current. Experimental results showed that the dark current was drastically reduced, and an avalanche multiplication phenomenon was observed at an applied voltage of over 6 V. However, this structure had sensitivity only in the ultraviolet light region because its depletion region was almost completely spread in the Ga2O3 layer since the carrier density of the Ga2O3 layer was much lower than that of the CIGS layer. These results indicate that the Ga2O3/CuGaSe2 heterojunction has potential for use in visible light sensors but that we also need to increase the carrier density of the Ga2O3 layer to shift the depletion region to the CIGS film.",

author = "Kenji Kikuchi and Shigeyuki Imura and Kazunori Miyakawa and Misao Kubota and Eiji Ohta",

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AU - Ohta, Eiji

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